code: def test_richclub4():
      G = nx.Graph()
      G.add_edges_from(
          [
              (0, 1),
              (0, 2),
              (0, 3),
              (0, 4),
              (4, 5),
              (5, 9),
              (6, 9),
              (7, 9),
              (8, 9),
          ]
      )
      rc = nx.rich_club_coefficient(G, normalized=False)
      assert rc == {0: 18 / 90.0, 1: 6 / 12.0, 2: 0.0, 3: 0.0}
  
file_path: networkx/networkx/algorithms/tests/test_richclub.py
imports: import pytest
  import networkx
label_desc: Use image node_id 6 for calling a global function with example usage: test_richclub4() without return types